Re: [TCLUG:14090] Disk I/O

["Eric M. Hopper" <hopper@omnifarious.mn.org>]

On Fri, Feb 25, 2000 at 08:16:53PM -0600, Christopher Reid Palmer wrote:
> Hi there,
> 
> I'm curious about how well my storage subsystem can perform, so I
> grabbed the benchmark program Bonnie and fired it up. I'd like to
> compare results with the rest of y'alls.
> 
> My hardware:
> ============
> K6 233, 66MHz bus (I think)
> Mylex/BusLogic Flashpoint Ultra SCSI (narrow) host adaptor
> IBM ?? model 7200 RPM SCSI u2w, /dev/sda
>     (with wide->narrow adaptor so it'll work with my SCSI card)
> Seagate Hawk 5400 RPM SCSI II, /dev/sdb
> 64MB RAM
> dusk:~ $ df
> Filesystem           1k-blocks      Used Available Use% Mounted on
> /dev/sda2              2966789    687679   2125690  24% /
> /dev/sda3              5560730   1964229   3308536  37% /usr/local
> /dev/sdb1              1018298    315351    650336  33% /backup
> 
> 
> 
> My results:
> ===========
> dusk:~/src/Bonnie $ ./Bonnie -s 100	# 100MB test file
> ...
>               -------Sequential Output-------- ---Sequential Input-- --Random--
>               -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
> Machine    MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU  /sec %CPU
>           100   849 86.9 12357 60.0  4009 32.1  1863 81.6 10625 26.5 144.8 4.2

	I think the abysmal stats you get for the character test are
actually because it's a CPU test.  If I'm guessing correctly, this is
reading or writing a character at time.  This basically measures how
fast you can make system calls, which are expensive because of the
context switch to the kernel.  Given this, 849K/sec is pretty amazing.
This means you can make 849,000 system calls a second.  On a 233MHz
machine, this means only 274 clock cycles per system call.  That's
pretty amazing, and a testament to the efficiency of the kernel.

	Of course, my guess could be wrong.  I'll have to read the
source to Bonnie to make sure.

Have fun (if at all possible),
-- 
Its name is Public Opinion.  It is held in reverence. It settles everything.
Some think it is the voice of God.  Loyalty to petrified opinion never yet
broke a chain or freed a human soul.     ---Mark Twain
-- Eric Hopper (hopper@omnifarious.mn.org  http://omnifarious.mn.org/~hopper) --

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